As a Project Manager (think resources, costs, quality, requirements) which requirement management tool would you invest in and why?

As a Project Manager (think resources, costs, quality, requirements) which requirement management tool would you invest in and why? How are you going to ensure that your "project" requirements are precise and met, to decrease rework and spent resources? What stakeholders would be involved in your requirements process? 

Please read: 

https://medium.com/the-digital-project-manager/the-best-requirements-management-tools-of-2019-e403de6c4adbLinks to an external site.

https://www.softwaretestinghelp.com/requirements-management-tools/Links to an external site.

https://thedigitalprojectmanager.com/tools/requirements-management-tools/